1. Field
The invention relates to a polyaxial bone anchoring device with an enlarged pivot angle. The bone anchoring device includes a bone anchoring element for anchoring in a bone or a vertebra, and a receiving part for coupling the bone anchoring element to a stabilization element such as a spinal rod, where the bone anchoring element is pivotable relative to the receiving part and can be pivoted away from a central axis with an enlarged pivot angle in at least one radial direction. The orientation of the enlarged pivot angle may be selectable within a range of 360° around the central axis. The bone anchoring element may be insertable into the receiving part from a bottom end of the receiving part.
2. Description of Related Art
A polyaxial bone anchoring device with an enlarged pivot angle that is selectable within a range of 360° around a central axis of the receiving part is known from US 2012/0136395 A1. This polyaxial bone anchoring device includes a sleeve-like insert piece that is positioned around a portion of the head of the bone anchoring element and that is configured to pivot in an accommodation space of the receiving part. The anchoring element and the insert piece can be locked at respective angles relative to the central axis of the receiving part. An enlarged pivot angle may be automatically achieved by pivoting the receiving part relative to the bone anchoring element in a specific direction. In one embodiment, the bone anchoring element may be inserted from the top end of the receiving part. In another embodiment, the bone anchoring element together with the sleeve-like insert piece may be inserted from the bottom end of the receiving part.
A polyaxial bone anchoring device of the bottom loading type are known, for example, from US 2010/0234902 A1.